


Kinktober 2020 - Day 27: Xenophilia (Swap Salphyne, NSFW)

by yastaghr



Series: Yastaghr's Kinktober 2020 [27]
Category: Undertale (Video Game)
Genre: Alphyne, Alternate Universe - Underswap (Undertale), Anniversary, Art, Crossdressing, Dildos, F/F, F/M, Graphic Description, Kinktober, Kinktober 2020, Memes, Multi, No Sex, Salphyne, Sundyne, Threesome - F/F/M, Underswap Alphys (Undertale), Underswap Sans (Undertale), Underswap Undyne (Undertale), Xenophilia, salphys, underswap alphys/sans/undyne
Language: English
Status: Completed
Published: 2020-10-27
Updated: 2020-10-27
Packaged: 2021-03-08 18:01:14
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 815
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27230893
Author URL: https://archiveofourown.org/users/yastaghr/pseuds/yastaghr
Summary: Undyne has come up with a gift they can all give each other for their anniversary. Alphys needs some convincing. Blue is in this, hook line and sinker.
Relationships: Alphys/Sans (Undertale), Alphys/Sans/Undyne (Undertale), Alphys/Undyne (Undertale), Sans/Undyne (Undertale)
Series: Yastaghr's Kinktober 2020 [27]
Series URL: https://archiveofourown.org/series/1947772
Comments: 2
Kudos: 18





	Kinktober 2020 - Day 27: Xenophilia (Swap Salphyne, NSFW)

**Author's Note:**

> going up to a new level of one of my pain meds, so hopefully that will go well!
> 
> new series coming nov 1!

“You did WHAT?!!” Alphys yelled.

Blue, who had been staring at his new collection of dresses, trying to decide which one to wear today, spun around in shock at the loud noise. His two mates, Alphys and Undyne, were laying on the bed, naked. They had been cuddling the last time he looked, but now Alphys looked both affronted and embarrassed. Undyne looked like she was going to fall off the bed laughing. 

“I learned how to make custom dildos so we can design presents for each other for our anniversary,” Undyne repeated, this time loud enough for Blue to hear. He felt his eyes start to sparkle. Oh, this was going to be fun!

Alphys spluttered. “B-b-but, why? Why would you do something like that?”

Undyne’s smile grew. “Don’t you mean, “Why would you do something so controversial and yet so brave?”, oh bearer of lightning?”

Alphys frowned when Blue sputtered with laughter. Then, slowly, a grin spread over her own face. “That was a meme, wasn’t it? Blue, where did that meme come from, and what does it mean?”

Blue grinned. “It’s from a human show, but it made its way onto the Undernet because of a wire tap that my b-b-brother made. It’s mostly a joke said over something simple to get a reaction, but I think this time Undyne wants to play it straight. Saying she learned how to make custom dildos is controversial, but saying she did it for our anniversary is brave! Does that make sense?”

Alphys beamed at him. “Yeah, it does, Blue. Thanks for the download,” Then she turned back to Undyne and said, “Now, why would you do that? We can get good dildos at the sex shop.”

“You don’t understand, Alph. We can make  _ anything. _ It doesn’t just have to be a dick, tentacle, or tongue. Like, we could make a spiky cucumber and ride it, or a palm tree.  _ Anything. _ I can see the ideas in your eyes, Blue. Why don’t you go into the other room? There’s some modeling clay and plaster on the table. you know how to make a mold, right? You can call one of us when you’re done. I promise I won’t look at the shape until we give it to each other. Just put your initial on the bottom somewhere. I think I need to help Alphys come up with some ideas.”

Blue slipped into his art dress and ran out into the main room of their apartment. There were indeed the supplies he’d need to do this. He picked the blue clay and got to work. 

For Alphys, the first thing that had popped into his head was a lightning bolt; not the stylized ones, but a real one, with branches and angles. He knew that, no matter what substance Undyne made this out of, that Alphys would love it. She had an overstimulation kink a mile long.

Undyne’s give was a crashing wave with foamy bubbles at the crest of it. The curl would hopefully hit her g-spot good. She had the best orgasms that way.

When both of his molded sculptures were completed, Blue encased them in a plaster shell. That way Undyne would have a negative mold to make the positive dildo out of. He hoped she let him keep his clay sculptures. He was really proud of them.

The next person to use the supplies was Undyne. She sort of… cheated. She’d actually commissioned an online friend of hers to make two 3D models, which she’d printed out on the lab’s system. One was a model of the final scepter from Alphys’ favorite magical girl anime for her scaly girlfriend. The other, which was for Blue, was a star nosed mole. He loved the little critters for some reason that she couldn’t understand. It wasn’t an entirely pure love.

The final member of their triad to come into the front room was Alphys. She was nervous, blushing, and sweating. Art wasn’t really her forte, but she didn’t want to disappoint her datemates, so she’d looked up some reference images.

The first dildo that she sculpted was for Blue. It was a little shooting star, very cartoony and simple, that she definitely didn’t measure to make sure could be used from both ends. The other one she made was a dna chain. The circles weren’t perfect, but it looked good enough to her. She was sure her science geek of a mate would either love it or think it was hilarious. Either way Alphys would count it as a win.

The dildos were a success! Eventually. It took Undyne eight tries to get them right, but they were worth it in the end. Everyone loved everything about them… other than that they were pink. None of them were big fans of pink. Unfortunately, that was the only color Undyne could get to hold together.

**Author's Note:**

> You can find me on:
> 
> Tumblr - https://yastaghr.tumblr.com  
> Twitter - https://twitter.com/yastaghr * Most active


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